Imaging systems have become exceedingly popular peripherals for computers and other types of computerized devices. They enable users to print images onto media, thus such imaging systems may also be referred to as printers. The most common media is paper.
There are many different types of imaging systems, including most popularly inkjet printers and laser printers. Inkjet printers generally operate by ejecting fine droplets of ink onto the media, whereas laser printers generally operate by fusing toner onto the media. Either type of imaging systems may be a black and white only printer or a color printer.
Due to manufacturing and operating environment variances, imaging systems typically have to be calibrated for optimal performance. Often times, a one-dimensional linearization look-up table (LUT) is generated during calibration for each color channel, for use during operation, to linearize the output intensities of the corresponding pen. For example, for a color imaging system employing a cyan-magenta-yellow-black (CMYK) color space, a linearization LUT would be generated during calibration for each of the cyan, magenta, yellow, and black color channels, for use during operation, to linearize the output intensities of each of the cyan, magenta, yellow, and black color pens.
Typically, each linearization LUT is generated based on a range of target outputs, and in view of a standard, i.e. by determining the amount of corresponding adjustments required for the corresponding pen, such that the pen's output intensities are linear over the range, as called for by the standard.
Regardless of the techniques, calibrations are inherently imperfect, as they are affected by the environmental conditions under which the calibrations are performed, and subject to measurement errors. Thus, even though two pens of the same color may be calibrated using the same target outputs, and in view of the same standard, the output intensities of the calibrated pens may nevertheless be slightly different, especially if the calibrations are performed at different times, under different environmental conditions.
More importantly, when two of these pens of the same color channel are involved in contributing to the imaging/printing of a media end product, the slight difference may be sufficient to be discernable by consumers of the media end product imaged/printed, resulting in the consumers forming an opinion of “poor” imaging/printing quality of the imaging system(s).
Two “slight different” pens may be involved in contributing to the imaging/printing of a media end product under a variety of scenarios. For example, two imaging systems, each having one of the two pens of a color channel, may be involved in the imaging/printing of the media end product. As another example, two pens of a color channel, as members of two sets of multi-color pens of an imaging system having two imaging engines, may be involved in imaging/printing the media end product. As yet another example, one pen of a color channel of a bidirectional imaging system, used in two imaging directions, with the pen having different linearization LUTs for the different imaging directions, may be involved in the imaging/printing of the media end product.